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Author(s):  
Tiina Föhr ◽  
Timo Törmäkangas ◽  
Hannamari Lankila ◽  
Anne Viljanen ◽  
Taina Rantanen ◽  
...  

Abstract Background Epigenetic clocks are composite markers developed to predict chronological age or mortality risk from DNA methylation (DNAm) data. The present study investigated the associations between four epigenetic clocks (Horvath’s and Hannum’s DNAmAge and DNAm GrimAge and PhenoAge) and physical functioning during a three-year follow-up. Methods We studied 63–76-year-old women (n = 413) from the Finnish Twin Study on Aging. DNAm was measured from blood samples at baseline. Age acceleration (AgeAccel) i.e. discrepancy between chronological age and DNAm age was determined as residuals from linear model. Physical functioning was assessed under standardized laboratory conditions at baseline and at follow-up. A cross-sectional analysis was performed with path models, and a longitudinal analysis was conducted with repeated measures linear models. A nonrandom missing data analysis was performed. Results In comparison to the other clocks, GrimAgeAccel was more strongly associated with physical functioning. At baseline, GrimAgeAccel was associated with lower performance in the Timed Up and Go (TUG) test and the six-minute walk test. At follow-up, significant associations were observed between GrimAgeAccel and lowered performance in the TUG, six-minute and 10-meter walk tests, and knee extension and ankle plantar flexion strength tests. Conclusions The DNAm GrimAge, a novel estimate of biological aging, associated with decline in physical functioning over the three-year follow-up in older women. However, associations between chronological age and physical function phenotypes followed similar pattern. Current epigenetic clocks do not provide strong benefits in predicting the decline of physical functioning at least during a rather short follow-up period and restricted age-range.


2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Indra Kumar Kasi ◽  
Mohinder Singh ◽  
Kanchhi Maya Waiba ◽  
S. Monika ◽  
M. A. Waseem ◽  
...  

Abstract Background Entomopathogenic nematodes (EPNs) have the potential to supersede larvicidal activity for the management of various insect pests. Result Lab experiments were conducted to test the pathogenicity of 2 EPNs local species; Steinernema feltiae and Heterorhabditis bacteriophora at different (IJs/cm2) concentrations against the cabbage butterfly, Pieris brassicae (L.). The native isolate was obtained from soil samples, collected from Rajgarh, Hamachi Pradesh, India. Petri dish bioassay used the EPNs species (S. feltiae HR1 and H. bacteriophora HR2) at the concentrations (0, 10, 20, 40, 80, 160 IJs/cm2). Based on the pathogenicity of the strains, only 2 isolates effectively showed larvicidal activity. The highest (%) (72.08 and 67.42%), at the 2nd instar larval mortality was recorded in the treatments with H. bacteriophora and S. feltiae at160 IJs/cm2, respectively. At the 4th instar larvae, respective larval mortality (85.38, 69.50%) was recorded in treatment with H. bacteriophora, and S. feltiae, respectively, at160 IJs/cm2. In case of pupae, the mortality rates were (62.12, 58.58%) for H. bacteriophora and S. feltiae, respectively, at 160 IJs/cm2; (74 and 12%) for both the tested EPNs, respectively, at 80 IJs/cm2. Percent of P. brassicae larval mortality treated with the tested EPN isolates was significantly higher than the untreated control. Results revealed that the percent of larval mortality significantly increased with the increase in time periods, being maximum at 72 h. S. feltiae and H. bacteriophora, strains showed potent larvicidal activity at low concentration even at 48 and 72 h of exposure. Conclusion This study revealed that the local strains of EPNs (S. feltiae HR1 and H. bacteriophora HR2) were found as a biocontrol agent against P. brassicae.


Insects ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 838
Author(s):  
Guang Zeng ◽  
Jun-Rui Zhi ◽  
Mao Ye ◽  
Wen Xie ◽  
Tao Zhang ◽  
...  

Exogenous calcium (Ca) has been used to induce host plant resistance in response to abiotic and biotic stresses, including from thrips attack. The aim of this study was to determine whether exogenously applied Ca affects the performance of Frankliniella occidentalis. We assessed the development time, total longevity, reproduction, and population parameters of F. occidentalis, and its preference choice on Ca-treated or untreated control kidney bean plants under laboratory conditions. The results showed that F. occidentalis fed on Ca-treated leaves had a longer developmental time but lower longevity (female and male) and fecundity than F. occidentalis fed on control leaves. Population parameters, including the intrinsic rate of increase (r), finite rate of increase (λ), and net reproductive rate (R0), were all found higher in control leaves than in Ca-treated leaves, and the mean generation time (T) was shorter. In preference choices, the number of thrips on control plants was higher than the number of thrips on Ca-treated kidney bean plants. Overall, our results indicated that exogenous Ca pretreatment on kidney bean plants affected the life history and preference choice of F. occidentalis, suggesting Ca might be used as a promising elicitor of inducible plant defense against thrips.


Author(s):  
Amanda Ayala ◽  
Jorge Toledo ◽  
Gabriela Pérez-Lachaud ◽  
Pablo Liedo ◽  
Pablo Montoya

Abstract Knowledge on reproductive strategies and host use in insect parasitoids is fundamental for biological control purposes. Superparasitism and multiparasitism, oviposition in a previously parasitized host by a female of the same or different species, respectively, may impact pest management decisions. Our objective was to determine the occurrence of superparasitism and multiparasitism in three species of native larval−pupal solitary endoparasitoids that attack Anastrepha Shiner species (Diptera: Tephritidae) in the Neotropical region, and the possible effect on offspring fitness parameters. Doryctobracon crawfordi (Viereck), Utetes anastrephae (Viereck), and Opius hirtus (Fischer) occur in sympatry in Mexico, and are currently under consideration for use as biocontrol agents. Experiments were conducted under laboratory conditions with females acting alone (self-superparasitism), females in groups of the same species (conspecific superparasitism), and females in mixed groups (multiparasitism). Our results showed that self-superparasitism is an uncommon strategy in the three native species and is rare under conditions of intraspecific competition. In the case of multiparasitism, a higher number of immature stages of U. anastrephae was observed, compared to those of D. crawfordi and O. hirtus. However, it is not clear yet if this was due to some adult female trait or to the competitive ability of the larvae. We conclude that most females of the native species studied appeared to avoid superparasitism, specifically when acting alone, suggesting a high discrimination ability, which is probably a result of a close relationship and evolutionary history with Anastrepha hosts.


2021 ◽  
Vol 11 (18) ◽  
pp. 8595
Author(s):  
Jerzy Skubis ◽  
Michał Kozioł

This paper reports the results of the analysis of measurements involving partial discharges (PD) occurring in the air using a corona camera (UV camera). The measurements were carried out in laboratory conditions and applied two electrode systems: needle–needle and needle–plate, in order to obtain various electric field distributions. The measurements of PDs, including a variety of alternatives, were carried out using a portable UV camera, taking into account the impact of the camera gain parameter and its distance from the PD sources. As a result, some important regularities and characteristics were identified that could significantly affect the ability to assess PDs by application of UV camera measurements. In addition, the results obtained can be employed for non-invasive diagnostic measurements performed on working power equipment and may be useful in further work on standardizing the result interpretation method obtained from measurements using a UV camera.


2021 ◽  
pp. 174425912110454
Author(s):  
Neal Holcroft

The thermal properties of closed-cell foam insulation display a more complex behaviour than other construction materials due to the properties of the blowing agent captured in their cellular structure. Over time, blowing agent diffuses out from and air into the cellular structure resulting in an increase in thermal conductivity, a process that is temperature dependent. Some blowing agents also condense at temperatures within the in-service range of the insulation, resulting in non-linear temperature dependent relationships. Moreover, diffusion of moisture into the cellular structure increases thermal conductivity. Standards exist to quantify the effect of gas diffusion on thermal conductivity, however only at standard laboratory conditions. In this paper a new test procedure is described that includes calculation methods to determine Temperature Dependent Long-Term Thermal Conductivity (LTTC(T)) functions for closed-cell foam insulation using as a test material, a Medium-Density Spray Polyurethane Foam (MDSPF). Tests results are provided to show the validity of the method and to investigate the effects of both conditioning and mean test temperature on change in thermal conductivity. In addition, testing was conducted to produce a moisture dependent thermal conductivity function. The resulting functions were used in hygrothermal simulations to assess the effect of foam aging, in-service temperature and moisture content on the performance of a typical wall assembly incorporating MDSPF located in four Canadian climate zones. Results show that after 1 year, mean thermal conductivity increased 15%–16% and after 5 years 23%–24%, depending on climate zone. Furthermore, the use of the LTTC(T) function to calculate the wall assembly U-value improved accuracy between 3% and 5%.


2021 ◽  
Author(s):  
Lionel Feugère ◽  
Olivier Roux ◽  
Gabriella Gibson

Background: Male and female mosquitoes of many species mate in swarms consisting of males and uninseminated females; males form station-keeping swarms and mating chases ensue as soon as a male detects the flight tones of a female. The auditory organs of mosquitoes have been reported to be the most sensitive among arthropods, enabling them to track their flying mate by the sound of the female's flight tones during mating chases. Previous studies on hearing thresholds have mainly used electrophysiological methods, which unfortunately limit the natural behaviour of the mosquitoes. This study explores male auditory behavioural sensitivity to female flight tones. Methods: We developed a behavioural method for measuring hearing sensitivity in swarming male mosquitoes. Free-flying male Anopheles coluzzii mosquitoes were released in a large arena (~2 m high x 2 m x 1 m) with a visually conspicuous object on the ground that stimulates swarming behaviour consisting of elliptical flight pattern over the object. Males were exposed to a range of natural and synthetic played-back sounds of female flight emanating from a speaker located at the same height as the swarm centre and 0.9 m away from it. We monitored the responses of males to female sound by recording the flight-tone and flight-dynamic responses of males. Calibrated sound-levels were measured at the swarm centre; the changing distances between the speaker and the flying males as well as other measurement uncertainties were taken into account to estimate the sound levels that males were effectively exposed to. Results: We show that the mean male behavioural threshold of particle-velocity hearing lies between 13-20 dB SVL (95%-CI). A conservative estimate of 20 dB SVL (i.e., less than a particle velocity of 0.5e-6 m/s) is already 12 to 26 dB less than most of the published electrophysiological measurements on Johnston's organ sensilla. Our results confirm, under laboratory conditions, the high behavioural hearing-sensitivity of swarming mosquitoes recently found with swarming Aedes communis in the field, and suggest a hearing threshold at least two times lower than that of published results (26 dB SVL or 1e-6 m/s particle-velocity). In addition, we established that 1) the first harmonic of Anopheles coluzzii female flight sound is sufficient for males to detect her presence, 2) males respond with a greater amplitude to single-female sounds than to group-female sounds and 3) males respond to the playback of single-female sound as much as to pure-sound at a constant frequency and amplitude.


2021 ◽  
Vol 25 (03) ◽  
pp. 763-768
Author(s):  
Henrique Trevisan ◽  
◽  
Thiago Sampaio de Souza ◽  
Angélica Maria Penteado-Dias ◽  

The current study describes the first record in South America and the sexual behavior of Cryptontsira parva (Muesebeck, 1941) (Hymenoptera, Braconidae, Doryctinae) parasitizing Lyctus brunneus (Stephens, 1830) (Coleoptera, Bostrichidae, Lyctinae). We also include a brief report of the ethological reproductive aspects the C. parva under laboratory conditions by providing information to support research on biological control of L. brunneus.


ALGAE ◽  
2021 ◽  
Vol 36 (3) ◽  
pp. 195-206
Author(s):  
Kevin Erratt ◽  
Irena Creed ◽  
Camille Chemali ◽  
Alexandra Ferrara ◽  
Vera Tai ◽  
...  

Increasing inputs of dissolved organic matter (DOM) to northern lakes is resulting in ‘lake browning.’ Lake browning profoundly affects phytoplankton community composition by modifying two important environmental drivers—light and nutrients. The impact of increased DOM on native isolates of red and green-pigmented cyanobacteria identified as Pseudanabaena, which emerged from a Dolichospermum bloom (Dickson Lake, Algonquin Provincial Park, Ontario, Canada) in 2015, were examined under controlled laboratory conditions. The genomes were sequenced to identify phylogenetic relatedness and physiological similarities, and the physical and chemical effects of increased DOM on cellular performance and competitiveness were assessed. Our study findings were that the isolated red and green phenotypes are two distinct species belonging to the genus Pseudanabaena; that both isolates remained physiologically unaffected when grown independently under defined DOM regimes; and that neither red nor green phenotype achieved a competitive advantage when grown together under defined DOM regimes. While photosynthetic pigment diversity among phytoplankton offers niche-differentiation opportunities, the results of this study illustrate the coexistence of two distinct photosynthetic pigment phenotypes under increasing DOM conditions.


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